SLIM, Japan’s Lunar Lander, Astonishingly Survives Second Night on the Moon

Most landers we send to the Moon will operate for one lunar day, or about two weeks on Earth, until they die from the extreme cold of the lunar night. But Japan’s Smart Lunar Lander (SLIM) has now survived two nights on the moon and continues to send images back to Earth, an amazing feat.

SLIM is Japan’s first lunar lander and becomes the fifth country to land a spacecraft on the lunar surface. When the plane landed on January 19, it was tilted and the solar panels could not provide enough power to continue operating for more than a few hours. After nine days, the sun began to move again, moving across the sky.

But just three Earth days later, the lunar night began. Nighttime temperatures on the moon can drop as low as -133°C (-208°F), potentially damaging the spacecraft’s batteries and electronics. Normally, the lunar lander shuts down on a lunar night and never wakes up again, but it started up again on February 25 as the sun rose above Slim.

This in itself was a surprise. The lander was not specifically designed to withstand lunar nights, and its original mission was scheduled to end at night. So, as night approached again, this seemed to be the end of SLIM.

However, on March 27th, the SLIM official account I posted an image above X has the following caption: “Last night, we received a response from SLIM confirming that SLIM achieved its second success during the night. Last night, the sun was still high and the equipment was hot, so I quickly turned on my navigation camera. It looks like the lander will be able to resume analyzing its surroundings within the next few days.

Its survival is especially surprising because while some spacecraft use radioactive elements to stay warm, SLIM does not. “This is a significant achievement considering we are not using radioisotope heaters,” he says. Haim Benaroya at Rutgers University in New Jersey. “This result is important and impressive, given that this is a major design consideration for electronics (and people) to survive moonlit nights.” SLIM has failed while many other spacecraft have failed. Analyzing how they survived may help us understand how they stay warm on the moon.